1 // SPDX-License-Identifier: GPL-2.0
2
3 #define DISABLE_BRANCH_PROFILING
4
5 #include <linux/kasan.h>
6 #include <linux/printk.h>
7 #include <linux/memblock.h>
8 #include <linux/sched/task.h>
9 #include <asm/pgalloc.h>
10 #include <asm/code-patching.h>
11 #include <mm/mmu_decl.h>
12
13 static pgprot_t __init kasan_prot_ro(void)
14 {
15 if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE))
16 return PAGE_READONLY;
17
18 return PAGE_KERNEL_RO;
19 }
20
21 static void __init kasan_populate_pte(pte_t *ptep, pgprot_t prot)
22 {
23 unsigned long va = (unsigned long)kasan_early_shadow_page;
24 phys_addr_t pa = __pa(kasan_early_shadow_page);
25 int i;
26
27 for (i = 0; i < PTRS_PER_PTE; i++, ptep++)
28 __set_pte_at(&init_mm, va, ptep, pfn_pte(PHYS_PFN(pa), prot), 1);
29 }
30
31 int __init kasan_init_shadow_page_tables(unsigned long k_start, unsigned long k_end)
32 {
33 pmd_t *pmd;
34 unsigned long k_cur, k_next;
35
36 pmd = pmd_off_k(k_start);
37
38 for (k_cur = k_start; k_cur != k_end; k_cur = k_next, pmd++) {
39 pte_t *new;
40
41 k_next = pgd_addr_end(k_cur, k_end);
42 if ((void *)pmd_page_vaddr(*pmd) != kasan_early_shadow_pte)
43 continue;
44
45 new = memblock_alloc(PTE_FRAG_SIZE, PTE_FRAG_SIZE);
46
47 if (!new)
48 return -ENOMEM;
49 kasan_populate_pte(new, PAGE_KERNEL);
50 pmd_populate_kernel(&init_mm, pmd, new);
51 }
52 return 0;
53 }
54
55 int __init __weak kasan_init_region(void *start, size_t size)
56 {
57 unsigned long k_start = (unsigned long)kasan_mem_to_shadow(start);
58 unsigned long k_end = (unsigned long)kasan_mem_to_shadow(start + size);
59 unsigned long k_cur;
60 int ret;
61 void *block;
62
63 ret = kasan_init_shadow_page_tables(k_start, k_end);
64 if (ret)
65 return ret;
66
67 k_start = k_start & PAGE_MASK;
68 block = memblock_alloc(k_end - k_start, PAGE_SIZE);
69 if (!block)
70 return -ENOMEM;
71
72 for (k_cur = k_start & PAGE_MASK; k_cur < k_end; k_cur += PAGE_SIZE) {
73 pmd_t *pmd = pmd_off_k(k_cur);
74 void *va = block + k_cur - k_start;
75 pte_t pte = pfn_pte(PHYS_PFN(__pa(va)), PAGE_KERNEL);
76
77 __set_pte_at(&init_mm, k_cur, pte_offset_kernel(pmd, k_cur), pte, 0);
78 }
79 flush_tlb_kernel_range(k_start, k_end);
80 return 0;
81 }
82
83 void __init
84 kasan_update_early_region(unsigned long k_start, unsigned long k_end, pte_t pte)
85 {
86 unsigned long k_cur;
87
88 for (k_cur = k_start; k_cur != k_end; k_cur += PAGE_SIZE) {
89 pmd_t *pmd = pmd_off_k(k_cur);
90 pte_t *ptep = pte_offset_kernel(pmd, k_cur);
91
92 if (pte_page(*ptep) != virt_to_page(lm_alias(kasan_early_shadow_page)))
93 continue;
94
95 __set_pte_at(&init_mm, k_cur, ptep, pte, 0);
96 }
97
98 flush_tlb_kernel_range(k_start, k_end);
99 }
100
101 static void __init kasan_remap_early_shadow_ro(void)
102 {
103 pgprot_t prot = kasan_prot_ro();
104 phys_addr_t pa = __pa(kasan_early_shadow_page);
105
106 kasan_populate_pte(kasan_early_shadow_pte, prot);
107
108 kasan_update_early_region(KASAN_SHADOW_START, KASAN_SHADOW_END,
109 pfn_pte(PHYS_PFN(pa), prot));
110 }
111
112 static void __init kasan_unmap_early_shadow_vmalloc(void)
113 {
114 unsigned long k_start = (unsigned long)kasan_mem_to_shadow((void *)VMALLOC_START);
115 unsigned long k_end = (unsigned long)kasan_mem_to_shadow((void *)VMALLOC_END);
116
117 kasan_update_early_region(k_start, k_end, __pte(0));
118
119 #ifdef MODULES_VADDR
120 k_start = (unsigned long)kasan_mem_to_shadow((void *)MODULES_VADDR);
121 k_end = (unsigned long)kasan_mem_to_shadow((void *)MODULES_END);
122 kasan_update_early_region(k_start, k_end, __pte(0));
123 #endif
124 }
125
126 void __init kasan_mmu_init(void)
127 {
128 int ret;
129
130 if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE)) {
131 ret = kasan_init_shadow_page_tables(KASAN_SHADOW_START, KASAN_SHADOW_END);
132
133 if (ret)
134 panic("kasan: kasan_init_shadow_page_tables() failed");
135 }
136 }
137
138 void __init kasan_init(void)
139 {
140 phys_addr_t base, end;
141 u64 i;
142 int ret;
143
144 for_each_mem_range(i, &base, &end) {
145 phys_addr_t top = min(end, total_lowmem);
146
147 if (base >= top)
148 continue;
149
150 ret = kasan_init_region(__va(base), top - base);
151 if (ret)
152 panic("kasan: kasan_init_region() failed");
153 }
154
155 if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) {
156 ret = kasan_init_shadow_page_tables(KASAN_SHADOW_START, KASAN_SHADOW_END);
157
158 if (ret)
159 panic("kasan: kasan_init_shadow_page_tables() failed");
160 }
161
162 kasan_remap_early_shadow_ro();
163
164 clear_page(kasan_early_shadow_page);
165
166 /* At this point kasan is fully initialized. Enable error messages */
167 init_task.kasan_depth = 0;
168 pr_info("KASAN init done\n");
169 }
170
171 void __init kasan_late_init(void)
172 {
173 if (IS_ENABLED(CONFIG_KASAN_VMALLOC))
174 kasan_unmap_early_shadow_vmalloc();
175 }
176
177 void __init kasan_early_init(void)
178 {
179 unsigned long addr = KASAN_SHADOW_START;
180 unsigned long end = KASAN_SHADOW_END;
181 unsigned long next;
182 pmd_t *pmd = pmd_off_k(addr);
183
184 BUILD_BUG_ON(KASAN_SHADOW_START & ~PGDIR_MASK);
185
186 kasan_populate_pte(kasan_early_shadow_pte, PAGE_KERNEL);
187
188 do {
189 next = pgd_addr_end(addr, end);
190 pmd_populate_kernel(&init_mm, pmd, kasan_early_shadow_pte);
191 } while (pmd++, addr = next, addr != end);
192 }
193
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